1. Field of the Invention
The present invention relates to a radio communication apparatus and a method for making a radio communication apparatus, and in particular to a radio communication apparatus configured to be used for a plurality of kinds of radio communication and a method for making such a radio communication apparatus.
2. Description of the Related Art
Wireless communication technology applied to identification is called radio frequency identification (RFID), and is widely used for automatic ticket gates, working hour management of companies and offices, various kinds of electronic money and so on. In an RFID system, information is transferred from a device called a reader/writer to a data medium called a card or a tag, and vice versa.
The reader/writer and the card each include an antenna formed by a coil-shaped element (sometimes called a loop antenna or a loop coil antenna). Upon putting the antennas in a state where the antennas face opposite each other and to communicate with each other, the reader/writer can write data onto the card and can read data from the card. Some kind of mobile phone is equipped with such a function corresponding to RFID.
A mobile phone has an antenna for mobile communication for a primary purpose of use. Moreover, a mobile phone equipped with a plurality of functions often has another antenna so as to work in a plurality of systems. In some cases, these antennas and the above antenna formed by the coil-shaped element are put close to each other due to limited mounting space. In such a case, the antennas can often be electromagnetically coupled with each other, resulting in that antenna characteristics are affected and a range or quality of communication is degraded.
In order to address such a problem, a mobile phone constituted by including an antenna for mobile communication and an antenna for RFID both formed on a same flexible printed board is known, e.g., as disclosed in Japanese Patent Publication of Unexamined Applications (Kokai), No. 2007-306287. According to JP 2007-306287, the antenna for mobile communication and the antenna for RFID are both formed on the same flexible printed board so that a space between the both antennas is kept constant and their characteristics are made stable. Moreover, an electromagnetic wave shield sheet is put on the flexible printed board so that interference between the reader/writer and a mother board of the mobile phone can be reduced.
The mobile phone disclosed in JP 2007-306287 keeps the space between the antenna for mobile communication and the antenna for RFID constant so as to make their characteristics stable, but does not prevent degradation of the characteristics caused by a coupling between the antennas. Thus, the characteristics may possibly be degraded due to the coupling and may level off depending on conditions.